A system of this type is known from U.S. Pat. No. 4,779,182. In this prior art system the corona discharge space is used to scrub a waste gas of foreign matter. The high voltage generating source supplies a high DC voltage to the corona wire inside the corona discharge space. The control electronics for controlling the operation of the high voltage generating source receives a signal from a measuring circuit measuring the high voltage supplied to the corona wire and receives furthermore signals indicating the amount of foreign matter in the gas to be treated at the input of the corona discharge space and at the output of the corona discharge space.
If this type of system has to be used on an industrial scale in general a high processing capacity is desirable. To obtain a high processing capacity in general a large electrical power has to be dissipated inside the corona discharge space. To restrict the current supplied to the corona wire the only way to increase the dissipated power is to increase the voltage level of the high voltage generating source. Very high voltages and still restricted power levels can only be obtained if, instead of a DC voltage, voltage pulses are supplied. The use of voltage pulses for powering a corona discharge space is known as such, see for instance U.S. Pat. No. 4,919,690 and U.S. Pat. No. 4,695,358.
A significant disadvantage of the use of high voltage pulses is the disturbing effect thereof.